Hi Earl,
> Regarding methods to attenuate strong BC signals when they are a problem
> on 160-meters, perhaps a better method would be to design a notch filter
> tuned to the frequency of the interfering signal. This would be much
> sharper than a bandpass filter and is certainly conceivable to implement
> if one is using a separate receive antenna.
A notch would be my first reaction also, but the component values
required are not commonly available when nulling 200 kHz. Also
padding the trap to frequency would be a "chore".
The most simple approach when components and frequencies are
considered is a high-pass T, a second option would be a parallel
network resonant on 160 across the line.
> MFJ effectively uses this method in their MFJ-731 tunable notch filter
> which is sold as an accessory for the MFJ-259B analyzer -- but if you buy
> the MFJ-731 for this purpose don't place it in your transmit antenna coax
> line!
That unit contains a variable notch that covers the AM BCB and a
parallel tuned circuit.
73, Tom W8JI
w8ji@contesting.com
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